The Infona portal uses cookies, i.e. strings of text saved by a browser on the user's device. The portal can access those files and use them to remember the user's data, such as their chosen settings (screen view, interface language, etc.), or their login data. By using the Infona portal the user accepts automatic saving and using this information for portal operation purposes. More information on the subject can be found in the Privacy Policy and Terms of Service. By closing this window the user confirms that they have read the information on cookie usage, and they accept the privacy policy and the way cookies are used by the portal. You can change the cookie settings in your browser.
Action recognition based on human skeleton structure represents nowadays a prosper research field. This is mainly due to the recent advances in terms of capture technologies and skeleton extraction algorithms. In this context, we observed that 3D skeleton-based actions share several properties with handwritten symbols since they both result from a human performance. We accordingly hypothesize that...
Augmented Reality (AR) is an active and exciting topic aiming to create intuitive computer interface by blending reality and virtual reality. One challenge of AR is to align virtual data with the environment. Typically, one uses a marker-based approach such as a thick-bordered black and white 2D marker which allows one to recover the relative pose (location and orientation) of a camera in real time...
The segmentation of the bone in HR-pQCT (High Resolution peripheral Quantitative Computed Tomography) images remains a challenging task due to the image characteristics and the complex structure of the bone (cortical and trabecular). In this paper, we address the problem of separating the cortical bone from the background and the trabecular bone. We propose a novel approach to segment the cortical...
In this paper, we propose a saliency detection model for RGB-D images based on the contrasting features of color and depth within a Bayesian framework. The depth feature map is extracted based on superpixel contrast computation with spatial priors. We model the depth saliency map by approximating the density of depth-based contrast features using a Gaussian distribution. Similar to the depth saliency...
We aim to reconstruct an accurate neutral 3D face model from an RGB-D video in the presence of extreme expression changes. Since each depth frame, taken by a low-cost sensor, is noisy, point clouds from multiple frames can be registered and aggregated to build an accurate 3D model. However, direct aggregation of multiple data produces erroneous results in natural interaction (e.g., talking and showing...
In this paper, we propose a new camera model for reconstructing 3D objects under light ray distortion caused by refractive medias. The proposed method can reconstruct 3D scene, even if light rays projected into the cameras are refracted by the refractive media, such as glasses and raindrops. For this objective, we represent light ray projection of multiple cameras by using a pair of planes shared...
Template matching is a technique for finding a part of reference image which matches a template image. This paper presents a new fast template matching algorithm which can detect the most similar position. In the proposed method, first, an effective initial threshold is calculated using Winner Update Algorithm. Next, very fast template matching is achieved by using this initial threshold in Multilevel...
Reconstruction of skulls from defective models is a very important and challenging task in craniofacial surgery, forensics, and anthropology. Existing methods typically reconstruct approximating surfaces that regard corresponding points on the target skull as soft constraints, thus incurring non-zero error even for non-defective parts and high overall reconstruction error. This paper proposes a novel...
We propose a fast calibration method for projector-camera pairs which does not require any special calibration objects or initial estimates of the calibration parameters. Our method is based on a structured light approach to establish correspondences between the camera and the projector view. Using the vanishing points in the camera and the projector view the internal as well as the external calibration...
Stereogram or autostereogram, frequently known as Magic Eye picture, is a two-dimensional (2D) image. Hidden inside each stereogram image is a floating object which appears in three-dimensional. We present a fully featured, web-based, online system that produces on-the-fly stereograms (or autostereograms) from a pair of side-by-side images. The system consists of three steps: (i) two side-by-side...
In this paper, we propose a new feature-point based RGB-D visual odometry approach for estimating the relative camera motion from two consecutive frames. The approach differs from most feature-point based RGB-D visual odometry approaches in two key aspects: (1) we do not directly use point correspondences to compute relative motion, instead, we link each two distinct points to form a line segment,...
We present theoretical results showing that deep neural networks require fewer parameters than a shallow network to achieve similar accuracy results on a simple classification problem where the decision boundary is a circle in two dimensions. In particular, shallow networks require O(1/√ϵ) parameters compared to O(log2[1/ϵ]) for a deep network to achieve an error rate of ϵ.
It is known that epipolar geometry can be computed from three epipolar line correspondences but this computation is rarely used in practice since there are no simple methods to find corresponding lines. Instead, methods for finding corresponding points are widely used. This paper proposes a similarity measure between lines that indicates whether two lines are corresponding epipolar lines and enables...
A new camera calibration approach is proposed that can utilize the affine transformations and surface normals of small spatial patches. Even though classical calibration algorithms use only point locations, images contain more information than simple 2D point coordinates. New methods are presented in this paper for the calibration problem with their closed-form solutions, then the estimated parameters...
This paper presents a multilevel analysis of 2D shapes and uses it to find similarities between the different parts of a shape. Such an analysis is important for many applications such as shape comparison, editing, and compression. Our robust and stable method decomposes a shape into parts, determines a parts hierarchy, and measures similarity between parts based on a salience measure on the medial...
Large vocabulary gesture recognition using a training set of limited size is a challenging problem in computer vision. With few examples per gesture class, researchers often employ exemplar-based methods such as Dynamic Time Warping (DTW). This paper makes two contributions in the area of exemplar-based gesture recognition: 1) it introduces Multiple-Pass DTW (MP-DTW), a method in which scores from...
Inferring scene depth from a single monocular image is an essential component in several computer vision applications such as 3D modeling and robotics. This process is an ill-posed problem. To tackle this challenging problem, previous efforts have been focusing on exploiting only global or local depth aware properties. We propose a model that incorporates both of them to obtain significantly more...
The diagnosis of disease with the aid of computer programs has been developing more and more in recent years. This paper presents an approach which is based on frequency technique for the objective quantitative analysis of facial paralysis. In this method, limited-orientation modified circular Gabor filters (LO-MCGFs) are used to enhance the desirable frequencies in images. Then, features are extracted...
In this paper we present a novel unsupervised feature representation by extracting salient symmetries in RGB-D images using the proposed moment-based symmetric patch detector. A fast indexing structure is also derived to group local symmetric patches into semantically meaningful symmetric parts. Given an RGB-D image, the hash-based symmetric patch indexing speeds up the searches of symmetric patch...
We present a Bayesian framework for estimating 3D human pose and camera from a single RGB image. We develop a generative model where a 3D pose is rendered onto an image (via the camera), which then generates a detection probability map for each body part. We represent a human pose with a set of 3D cylinders in space, one for each body part, and we place kinematic and self-intersection priors on the...
Set the date range to filter the displayed results. You can set a starting date, ending date or both. You can enter the dates manually or choose them from the calendar.